Answer:
6 Hours
Step-by-step explanation:
Time Taken = Distance Travelled/Speed
Speed = 60 miles per hour
Distance Travelled = 300 miles
Time taken = 300/60 = 5 hours
Speed (if he reduces his speed by 10 miles per hour) = 60-10 = 50 miles per hour
Distance = 300 miles
Time Taken = 300/50 = 6 hours